The member function addDimensions is used to create the three dimensions--weight, time, and distance--and add them to the model. You must explicitly add the dimensions to the model or Solver will not be able to use them in the search for a solution.

The following code is provided for you:

void RoutingModel::addDimensions() {

Next, you create the weight dimension.

Add the following code after the comment
//Create the weight dimension and add to model

  _weight =IloDimension1 (_env, "weight");
  _mdl.add(_weight);

The dimension _weight is an instance of the subclass IloDimension1. Weight is a dimension that is intrinsic to an object and depends only on that object. For example, a vehicle can carry a certain amount of weight or a visit can require a vehicle to drop off or pick up a certain amount of weight. The constructor for IloDimension1 used in this lesson takes two parameters: the environment and a name used for debug and trace purposes.

Now, you create the time and distance dimensions.

Add the following code after the comment
//Create the time and distance dimensions and add to model

  _time  =IloDimension2 (_env, IloEuclidean, "time");
  _mdl.add(_time);

  _distance =IloDimension2 (_env, IloEuclidean, "distance");
  _mdl.add(_distance);
}